我将“引用类型”传递给函数“BY VAL”。在函数中我试图修改foreach循环中的引用类型。
然后说到来电者, 我通过的对象没有得到更新。 但是返回更新的对象。
我在下面给出了这个问题的例子。
有人可以花几分钟帮助我为什么会这样吗?
以下是方法GetStudents(),FilterStudents(), 课程,学生,老师,SSCClass,
SSCClass - 包含教师数组。 老师 - 包含学生数组。
public void GetStudents()
{
Student[] sscStudentsOne = new Student[] { new Student { V_SId = 1, V_SName = "Kumar" }, new Student { V_SId = 2, V_SName = "Varun" }, new Student { V_SId = 3, V_SName = "Murthy" } };
Student[] sscStudentsTwo = new Student[] { new Student { V_SId = 4, V_SName = "Sathya" }, new Student { V_SId = 5, V_SName = "Krishna" }, new Student { V_SId = 6, V_SName = "Bindu" } };
Teacher[] sscTeachers = new Teacher[] { new Teacher { V_tId = 1, V_tName = "Jyothi", V_Students = sscStudentsOne }, new Teacher { V_tId = 2, V_tName = "Srinivas", V_Students = sscStudentsTwo } };
SSCClass objSSCClass = new SSCClass();
objSSCClass.V_sscTeachers = sscTeachers;
SSCClass objSSCClassFiltered = FilterStudents(objSSCClass);
// Problem :-
// in objSSCClass Kumar is getting removed but Sathya from second teachere is not getting removed.
// in objSSCClassFiltered Kumar and Sathya are Getting removed as we did.
// We need objSSCClass object to be updated successfully .. as we can not return this to caller method in my project.
}
public SSCClass FilterStudents(SSCClass objSSCClasstobeFiltered)
{
foreach (Teacher item in objSSCClasstobeFiltered.V_sscTeachers)
{
// here a method will be called and does the below
// removes Students based on some criteria
// Say,
// Remove Student Kumar from first teacher.
// Remove Student Sathya from second teacher
}
// after filtering Students return the SSC Class object
return objSSCClasstobeFiltered;
}
public class Student
{
int v_sId;
public int V_SId
{
get { return v_sId; }
set { v_sId = value; }
}
string v_SName;
public string V_SName
{
get { return v_SName; }
set { v_SName = value; }
}
}
public class Teacher
{
int v_tId;
public int V_tId
{
get { return v_tId; }
set { v_tId = value; }
}
string v_tName;
public string V_tName
{
get { return v_tName; }
set { v_tName = value; }
}
Student[] v_Students;
public Student[] V_Students
{
get { return v_Students; }
set { v_Students = value; }
}
}
public class SSCClass
{
Teacher[] v_sscTeachers;
public Teacher[] V_sscTeachers
{
get { return v_sscTeachers; }
set { v_sscTeachers = value; }
}
}
答案 0 :(得分:0)
您无法更新Foreach
参考,创建一个新的,然后更新它:
Foreach (Student s in student_list)
{...
S s2 = s;
s2 = newval;
...}